The production rate of a furnace, such as a cement kiln, especially one which is directly fired by a fuel/ air main combustion reaction, may be increased by lancing oxygen into the furnace to augment the main combustion reaction. However, the use of oxygen may cause an increase in the formation of nitrogen oxides (NO.sub.x). Nitrogen oxides are environmentally deleterious and their excessive formation in a production process is undesirable.
Accordingly it is an object of this invention to provide an improved oxidant lancing nozzle which may be used to effectively inject oxidant into a combustion zone, especially directly into a fuel stream or a fuel/air mixture.
It is another object of this invention to provide a method for lancing oxidant into a combustion zone in a manner which will not cause increased NO.sub.x formation.
It is a further object of this invention to provide an improved oxidant lancing nozzle and method which will improve flame stability relative to the situation where only air is used as the oxidant.